Apparatus for making white lead.



C. ELLIS.

APPARATUS FOR MAKING WHITE LEAD.

APPLICATION FILED AUG.Z5. 191x.

1 1 44,70 I Patented J 11116 29, 1915.

UNITED STATES PATENT OFFICE.

CARLETON ELLIS, OF MONTCLAIR, NEW JERSEY, ASSIGNOR T0 ELLIS-FOSTERCOMPANY, i A CORPORATION OF NEW JERSEY.

APPARATUS FOR MAKING WHITE LEAD.

Application filed August 25, 1911.

To all whom it may concern.-

Be it known that I, CARLETON ELLIS, a citizen of the United States, anda resident of Montclair, in the county of Essex and State of New Jersey,have invented certain new and useful Improvements in Apparatus forMaking IVhite Lead, of which the following is a specification.

This invention relates to a process of making white lead and similarpigments, and to apparatus therefor; and relates particularly to theprocess and apparatus for manufacturing white lead in a substantiallycontinuous manner: all as more fully hereinafter described and asclaimed.

The manufacture of white lead by the old Dutch process involvestreatment of the metallic lead under corroding conditions for a space oftwo or three months, and on account of the protracted time required forthe complete corrosion of the lead, together with the labor costinvolved in handling the raw and finished product, the cost of manufacturing white lead by this process is relatively high. F or thisreason numerous processes have come into existence which involve thepreliminary connninution of the metallic lead in some way, andsubsequent treatment of the comminuted product with air, carbon dioxidand moisture; sometimes in the-presence of acetic acid or other similarchemical reagents. The old Dutch process as well as the quicker methodsof corrosion usually require soft refined lead. Suitable corroders leadgenerally commands an extra price and is expected to be free from suchimpurities as iron, copper, antimony and arsenic. If these impuritiesare present they constitute a source of much trouble and irregularity inthe processes of corrosion. Copper and iron both tend to discolor theresulting pigment. Antimony has a peculiar inhibiting action oncorrosion. In large proportion it may even check corrosion altogether.Vv'hen litharge is found present in large amount in the corroded stockthe trouble may often be traced to antimony. In the old Dutch processthe uncorroded lead, buckle residues and the like. are largely removedby rolling and washing. Inthe quirk processes of making white. lead.depending on the corrosion of comniinuted lead by the action of air,moisture and carbon dioxid, with perhaps acetic Specification of LettersPatent.

Patented June 25), 1915.

Serial No. 645,913.

or other acid present in small amount as a carrier, the removal of theunchanged or blue lead presents some difiiculties and in some cases maybe' wholly impracticable. Hence complete conversion of the lead would bedesirable, or failing that, a method which produces the minimum amountof blue lead and in a form readily separable from the corroded lead.Sandy lead. which forms in the Dutch process when the temperature of thecorroding' pots becomes too high. is a crystalline neutral carbrmate. Itis dillicui't to grind, lacks body and settles to the bottom of thecontainer when thinned for paint ing. Sandy lead appears in the productof the quick processes, at times, especially if the metallic lead hasbeen poorly or irregularly comminuted and the subsequent process ofcorrosion, in consequence, forced to the extreme, in an endeavor toovercome the defects of comminution. Again, in the quick processes thehydration of the lead largely precedes the carbonation stage .and infactin some cases it is probable that this separation of the tworeactions is essential.

In the present invention hydration and caibmmtion, if desired. may becarried out substantiall simultaneous y, with a consid erable saving intime. alu and apparatus.

The present invention set also that organization which makesP0,..Jlblfi2 the use of hard lead, which leads to the substantialreduction or elimination of blue lead and sandy lead and bysubstantially continuous operation or non-cumulative handling of thematerial throughout the major portion of the several operations involvedeffects a reduction in the cost of manufacture of the product. In thehandling of a material involving so great a tonnage as white lead, smallreductions in manufacturing costs effect a considerable total saving.

The process herein set forth also involves an especially thorough anduniform comminution of the metallic lead, preferably with thesimultaneous formation of a coat ing of a peculiar suboxid on the minuteparticles or filaments ot' the metal. The hydration of comminutcdleadmay lead to the formation of several different hydrates and the progressof carbonation as well as the character of the final product dependsvery largely on the nature of the initial hydration, which, other thingsbeing equal, is

controlled by the degree and uniformity of comminution and the characterof its surface coating of oxid, or absence of oxid, as

the case may be. 'Simulutaneous hydration and carbonation of irregularlycomminuted lead usually leads to the formation of ob -jectionable sandylead and excessive amounts of blue lead. I

' The present application contains matter which is contained in SerialNos. 570,214 and (511.606.

The manner in which the present inven- \tion is carried out will beclear from the accompanying diagrammatic drawings, (not to scale)wherein Figure 1 shows the assembled apparatus in section and elevation;while Figs. 2 and 3 show certain nozzle types or metal atomizers insection. Fig. i shows a centrifugal comminuterin plan view. Fig. 5depicts a plan view of a set of conveyers-and Fig. 6, shows thisconstruction in longitudinal'elevation.

As stated, the drawings are purely diagranmiatic, for the sake ofsimplicity of illustration. and are to be regarded as apreferred orillustrative embodiment wherein various changes or modifications may bemade without departing from the spirit of the. invention. 7

' In the drawings, 1 is a melting pot having the grate 2. andcomminuting nozzle 3.

A pipe 1 extends down through the pot and terminates in the nozzle 3.The latter is fitted with a conical disintegrator 5. Beneath the pot isplaced a receptacle (3 having an outlet 7, leading into the conveyortrough 3. The interior of this trough is shown by the eXposed portion orsection at 9, where propelling blades are seen mounted on a horizontalshaft. The conveyor and its various parts should be constructed ofmate-- rial which has no discoloring action. on the product. In order toaiford proper time contact the conveyor is of very considerable length.jacket 10 is provided. into which steam ma y be admitted through thepipe 11; an outlet beingprovided at 12. ()r 12 may be. used as the inletand 11 the outlet according to circumstances. \Vhen cooling is required,cold water may be admitted into this jacket to control the reaction.Inlets, 22. 2 -3 and 21 and also 25, 26 and 27 are provided for theintroduction of air. moisone end 28 to form a. nozzle opening 29.

plied with Metal duets 32 and 33 terminate within this casing-to formtips or metal nozzles angu larly disposed with respect to each other, fy as shown by 30 and 31. An air or steam pipe; 35 terminates in thenozzle 35' adjacent to the metal tips 30 and 31.

In Fig. 3' an annular chamber '31 is sup-l air, steam and the like bythe 37 and 38. 36 is the metal sup 39 and 10 are conical disintegratorsplaced in front of the casing 3, in

inlet pipes P y P P operative relation to the tip or nozzle thereof.

-' In Fig. & a rotatable drum 41 contains the molten metal, which isdischarged through the outlets 442. 13 is an annular slot through whichair, steam and the like are discharged 7 against the issuing streams ofmolten metal.;

The operation of the apparatus under the present invention is as follows:\Iolte1r lead or any suitable lead alloy fills the melting pot 1. Themetal, preferably should be in a super-molten condition. or at a temperature some or 500 degrees above the 111eltiD"f P0iI1t. The c lumn ofmetal preferably snould be high so as to furnish a very great pressureor head at the nozzle 3. The

metal is allowed to pass slowl} into the com-.

minuting nozzle 3 and air or steam under high pressure introduced by thepiped. Connninution of the metal takes place and I as the stream passesthrough the conical connmnuter 5 further reduction occurs, due

in part to vortex action of the air or steam current. The hnely db andwired rawing vided metal is collected in the chamber 6 J and isdischarged from thence in a regulable is passed slowly along theconveying cl1an1- her and is there Sllhjtttfll to the action of mannerinto the. converting conveyor It moisture and oxygen or a r toaccomplish jacket in lieu of steam. Car on dioXid may lhe material is atlength discharged from I or begin the reaction of hydration. In the 4case of a hard lead steam ma): he admitted into the jacket 10 to hastenthe reaction- Very reactive leads may lmiliil'e cooling. inv j whichcase cold water is admitted into the also be introduced into theconveying chains! her in order to secure )artial carbonation.

the first conve ver or conveyer system and passes into the separator 1-twhere it is freed from undesirable metallic particles and thus purifiedit passes into the carhonatingcham her 17 where. in contact withmoisture and carbon (lioxnl. and air if necessary. hnal' conversiontakes plaee'and the product discharged at 21. After drying the productais read} to be packaged for shipmcpt ground in Ull. 'lhe' comminutingnuz herein shown are depu-ted in several espeeially to emphasize theneces ity of cart- I ful and uniform comnnnution of the metal to anexcessively fine state. '1 he importance,

of length of travel of the hydrating and car bonating mass is alsoemphasized. The time contact factor may be increased without undulyincreasing the length of the conveying system by the cyclic or shunttreatment shown in Figs. 5 and 6. In Fig. 5, which is a plan view of aset of conveyers, 44 represents the feed end and 46 the discharge end.45, 47, 4S and 49 indicate conveyers operating in a manner to propel thematerial as indicated by the arrows. In Fig. 6, which is a longitudinalelevation of Fig.5, the conveyer 46 is shown as somewhat elevated abovethe bottom of the other conveyers, thus forming the dam 50. One or moreof these cyclic or shunt conveyers may be placed in the conveying lineof the hydrating and carbonating apparatus above set forth. Theoperation is as follows ;material traveling along the conveyer line 44and 45 reaches the dam 50, where the lighter portion of the materialpasses on by way of the conveyer 46. The heavier portion is caught bythe conveyer 47, delivered to conveyer 48 and from thence by conveyer 49reaches the feed end 44, thus making a complete cycle or shunt return.Meanwhile hydration or hydration and carbonation are in progress as thematerial is being constantly subjected. to corroding infiuences;air,water, steam, acetic acid, carbonic acid and the like, so that onarrival again at the dam 50 more conversion has occurred and the lighterproducts pass away by the conveyer 46. Fresh material is sup-' pliedconstantly at the feed end 44 to make up the loss by withdrawal of thematerial in an advanced stage of corrosion at 46.

Ordinarily it is not necessary to make use of acetic acid or otherstrong chemical agent, as air, moisture and carbon dioxid togetherreacting on the comminuted lead of a substantially uniform degree ofextreme fineness accomplishes this result effectively and produces apigment of especially high covering power. The use of acids or otherreagents is not however debarred in the present process. Instead of air,pure oxygen or oxygen and nitrogen mixtures having the former componentin larger proportion than is present in air, may be used. A high oxygencontent leads to more rapid oxidation and hydration. The influence oftemperature also is marked, slight increases in the temperature showingan immediate response in the rate of hydration. The eifect of using ahigh concentration of carbon dioxid, especially in the later stages ofcarbonation is also noticeable. Lime kiln gases, carefully washed,carrying 30% to 40% of carbon dioxid are useful. Pure carbon dioxid alsomay be used. A mixture of oxygen and carbon dioxid, without any dilutinggas, may be used for forced operation.

As stated, the degree of fineness of the filamentous or comminuted leadis a most important consideration. Excessive comminution to a degreedouble or triple that heretotore practised in the art is one of thefirst considerations leading to a high grade product of pronouncedcovering power. So far as I am advised, ordinary impingement of a jet ofair or steam and the like has not been carried out in a mannerafiording. a product of the requisite degree of fineness to makepossible the substantially continuous hydration and carbonation of atraveling stream, yielding a product of a satisfactory amorphous andfree-working qualities. This defect of imperfect comminution may be inpart due to the cooling effect of expansion of the compressed fluid jet.3

For example, superheated steam under high pressure, suddenly ejectedthrough an orifice and expanded to atmospheric pressure, falls 1ntemperature sometimes many hundred degrees through absorption of heatadapted to comminute lead to a product of extreme fineness, a conveyerof great length adapted to propel the comminuted product, a shunt returnforming a part of said conveyer, means for contacting said product whilein said conveyer with air in the presence of moisture; whereby saidproduct is hydrated; a separator connected with said conveyer adapted tofree the hydrated material from substantially all metallic particles, asecond conveyer adapted to receive and propel the hydrated material fromsaid separator, and means for introducing carbon dioxid into'said secondconveyer; whereby the hydrated material is carbonated.

2. An apparatus for making white lead comprising a receptacle forholding molten lead, adjacent thereto a metal atomizer adapted tocomminute lead to a product of extreme fineness, a conveyer of greatlength adapted to propel the comminuted product, means for contactingsaid product while in said conveyer with air in the presence ofmoisture; whereby said product is hydrated; a separator connected withsaid conveyer adapted to free the hydrated material from substantiallyall metallic particles, a second conveyer adapted to receive and propelthe hydrated material from said separator, and means for introducingcarbon dioxid into said second conveyer; whereby the hydrated materialis carbonated.

3, Apparatus for making White lead comprising a receptacle for holdingmolten lead, adjacent thereto a metal atomizer adapted to comminutemolten lead to a finely divided product, a conveyer adapted to propelthe comminuted product in contact with moisture and with oxygenating andcarbonating gases, and interposed in said conveyer a separator adaptedto remove metallic par- I ticles from the material.

day of August A D. 1911.

Witnesses NATHANIEL L. Fos'rrm, CHARLES WRIGHT.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. C.

OARLETON ELLIS.

